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Manganese phosphate removal from steel. What chemicals will do this?
Q. I have an occasional need to strip manganese phosphate coatings from finished steel parts for dimensional inspection. I need a chemical solution that will remove the coating without attacking the base metal. Any help would be appreciated, Thank you, John
John D'Annunzio.technician - Bohemia, New York
January 20, 2010
publicly reply to John D'Annunzio.
A. This is done all the time by those firms doing manganese phosphate and having to determine coating weight. Coated steel coupons of known are weighed, the coating stripped in hot chromic acid solution and then reweighing the stripped, bare and unetched steel coupon. The whole basis of this method of determining the coating weight is that the strip doesn't touch the steel - only the phosphate is dissolved. Check out the DOD-P-16232 [ed. note: replaced by MIL-DTL-16232 [from DLA] ] or any manganese phosphate spec for the details.

Milt Stevenson, Jr.
Syracuse, New York
publicly reply to Milt Stevenson, Jr.
"hot chromic acid solution"
Would this process also remove Zinc Phosphate? I was given a gun barrel that needs the coating removed because it was also coated on the inside of the barrel. I think its Zinc because its lighter in color than manganese.
Thanks for your time,
- MPLS, Minnesota
publicly reply to Mitch Shepard
Q. How to remove manganese phosphate coating on steel to measure the coating mass?
Shashi Kumarconsultant - Bangalore, Karnataka, India
January 27, 2014
publicly reply to Shashi Kumar
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